US 3910218 A
A propellant-actuated direct embedment anchor which utilizes simplified structural shapes and provides a rapid keying feature which allows the most efficient use of penetration energy. The anchor system has two major parts; a launch vehicle and a projectile which include a piston and fluke. Two different fluke designs are provided to satisfy the realm of anticipated seafloor conditions (sand, clay, and rock). The flukes designed for said and clay are similarly configured plate-like projectiles which only differ in length. The fluke designed for rock anchoring is a three-fin, arrowhead-shaped projectile, specially configured to penetrate rock and resist a specified pull-out load. The launch vehicle consists of a launching system, a reaction vessel and a firing mechanism. The firing mechanism is comprised of a weighted touch-down rod with a square base pad and a safe-and-arm device. The sand and clay flukes use a quick-keying design to maximize efficiency and holding power after embedment.
Claims available in
Description (OCR text may contain errors)
Taylor et al.
Oct. 7, 1975 PROPELLANT-ACTUATED DEEP WATER ANCHOR  Inventors: Robert J. Taylor, Camarillo;
Richard M. Beard, Oxnard, both of Calif.
 Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.
 Filed: Feb. 4, 1974 21 Appl. No.: 439,486
 U.S. Cl 114/206 A  Int. Cl. B63B 21/28  Field of Search 114/206 A, 207, 208 R, 114/209; 52/155, 160-164; 61/53, 68
 References Cited UNITED STATES PATENTS 3,170,433 2/1965 Gardiner 114/206 A 3,291,092 12/1966 Halberg et al. 114/206 A 3,372,665 3/1968 Mesler 114/206 A 3,520,268 7/1970 Bower.... 114/206 A 3,621,805 l1/l97l Smith 114/208 R Primary Examiney,-Trygve M. Blix Assistant Examiner-Stuart M. Goldstein Attorney, Agerit 0r Firm Richard S. Sciascia; Joseph M. St.Amand; Dali/id OReilly  ABSTRACT A propellant-actuated direct embedment anchor which utilizes simplified structural shapes and provides a rapid keying feature which allows the most efficient use of penetration energy. The anchor system has two major parts; a launch vehicle and a projectile which include a piston and fluke. Two different fluke designs are provided to satisfy the realm of anticipated seafloor conditions (sand, clay, and rock). The flukes designed for said and clay are similarly configured plate-like projectiles which only differ in length. The fluke designed for rock anchoring is a three-fin, arrowhead-shaped projectile, specially configured to penetrate rock and resist a specified pull-out load. The launch vehicle consists of alaunching system, a reaction vessel and a firing mechanism. The firing mechanism is comprised of a.weighted touch-down rod with a square base pad and a safe-and-arm device. The sand and clay flukes use a quick-keying design to maximize efficiency and holding power after embedment.
15 Claims, 8 Drawing Figures US. Patent Oct. 7,1975 Sheet 2 of3 3,910,218
US Patent Oct. 7,1975 Sheet 3 of3 3,910,218
PROPELLANT-ACTUATED DEEP WATER ANCHOR BACKGROUND OF THE INVENTION The present invention relates to anchors for deep ocean-anchorage and more particularly relates to anchors of the direct embedment type.
Deep ocean anchorage has long been a neglected area of development. There is a great demand for longterm deep ocean anchorage for sophisticated structures, weather buoys, surface and sub-surface instrument arrays, and numerous other types of construction. Presently, there are a number of types of anchors used to satisfy the anchorage requirements of these structures. Among these are the conventional drag or deadweight anchors which are ill-suited to the demands imposed on them in the deep ocean. The conventional drag anchor is embedded into the sea bottom by lateral dragging to develop horizontal pull resistance. In many anchoring situations, resistance to uplift forces is a prime consideration, and anchors relying upon horizontal dragging to ensure embedment generally provide minimum resistance to uplift forces. Also, embedment of the anchor by lateral drag is ordinarily impractical at depths below 500 feet.
The direct embedment anchor appears to be better suited to the requirements of deep ocean anchorage than the drag or dead-weight anchor. Two advantages of the direct embedment anchor are the capabilities to embed directly into the bottom without the necessity of dragging, and to resist significant uplift loads. One type of direct embedment anchor is embedded by either free-fall impact or by vibration and is a considerable improvement over the drag type anchor. However, there is still a need to provide simple, reliable and economical direct embedment anchors to improve ease and speed of installation and uplift resistance because long-term deep water use of the direct embedment anchor requires expendability.
SUMMARY OF THE INVENTION The purpose of the present invention is to provide a direct embedment anchor which shortens the lowering and placement time, enhances the precision of placement. and maximizes holding power. The present invention is a direct embedment anchor which utilizes a propellant-actuated launch vehicle and various fluke designs to achieve the above purposes. Two types of fluke designs are provided; one for sediment and another for rock. The sediment fluke employs a bent plate design to provide low penetration resistance for embedment and also employs a quick-keying feature to maximize holding power after placement. The rock fluke is a three-fin arrowhead-shaped projectile which offers minimum resistance to penetration while achieving substantial uplift resistance after embedment. The
launch vehicle is a propellant-actuated gun which is fired by a mechanism including a safe-and-arm device and a touchdown probe attached to and extending beyond the tip of the fluke. The launch vehicle also includes a reaction vessel in which the gun and safe-andarm mechanism are housed. An anchor down-haul cable is flaked on a board or plate attached to the launch vehicle.
OBJECTS OF THE INVENTION It is an object of the present invention to provide a direct embedment anchor with improved ease and speed of installation.
Another object of the present invention is to provide a direct embedment anchor utilizing a propellant actuated embedment technique.
Still another object of the present invention is to provide a direct embedment anchor system employing a fluke designed for embedment in sediment.
Another object of the present invention is to provide a direct embedment anchor system having a quickkeying feature for the sediment fluke design to maximize resistance to uplift forces after embedment.
A further object of the present invention is to provide a direct embedment anchor which has a fluke design for embedment in rock.
Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of the propellant actuated direct embedment anchor system with the sediment fluke.
FIG. 2 is a schematic diagram of the safe-and-arm device of the anchor propulsion system.
FIG. 3 is a diagram of the launch vehicle anchor propulsion system.
FIG. 4 is a perspective view illustrating the design of the sediment fluke.
FIG. 5 is a perspective view illustrating the design of the rock fluke.
FIG. 6 is a view of the direct embedment anchor system sediment fluke and piston after penetration and embedment is complete.
FIG. 7 illustrates the quick-keying feature of the sediment fluke in which a small pull on a cable initiates rotation of the fluke to its maximum uplift resistive position.
FIG. 8 illustrates the direct embedment anchor system sediment fluke and piston in keyed position for maximum uplift resistance.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The direct embedment anchor system is shown in FIG. 1 and has a launch vehicle, generally indicated at 10 and a sediment fluke 12. The launch vehicle 10, consists of a reaction vessel and a propulsion system. The reaction vessel is composed of a thick plate 17 welded to a heavy steel pipe or tube 22. The plate 17 and tube 22 are attached by bolting to a bearing plate 18 that is threaded on the breech end of gun barrel 24.
The anchor system performance is improved by increasing the ratio of launch vehicle mass to projectile mass. However, a point of diminishing returns is reached when this ratio is about three. Thus, the mass of the reaction vessel was made great enough to give a 3-to-1 ratio between the launch vehicle and the heaviest projectile (i.e., the clay fluke), thereby giving an even larger ratio with the lighter projectiles. Trapped water further increases the reaction mass, but the magnitude of this effect is difficult to assess. Previous embedment anchor designs have relied on trapped water to provide a large portion of the required reaction mass, but this procedure results in more complex structural configurations which are difficult and costly to fabricate. Trapping water for a significant part of the reaction mass does reduce the on-ship mass to be handled but since these anchors are a relatively light piece of equipment the simpler and less costly approach of using steel for the reaction mass is more advantageous.
Propulsion of the sediment fluke 12 is achieved through a piston 26 and piston extension arm 28. Piston extension arm 28 is mechanically connected to the sediment fluke 12 by link arm 30 and coupling link 32. When the anchor system is assembled for launching, the sediment fluke 12 is held tightly against the end of piston extension arm 28 by turn-buckles 34 brackets 36 and shear pins 38. After launching, fluke-piston extension arm contact is maintained during initial penetration by the inertial force of the piston 26, and in later stages of penetration because soil drag on fluke 12 exceeds that on the piston 26. This arrangement facilitates keying because no mechanical connection between piston extension arm 28 and fluke 12 need to be severed prior to initiating keying of the fluke 12.
A downhaul cable 76 is secured to the piston extension arm 28 by a pin 78 and is flaked on a board or plate (not shown) attached to the launch vehicle 10. A length of 75 feet for the downhaul cable 76 will account for a maximum penetration of 50 feet in soft clay and a predicted 25 feet of launch vehicle recoil at full charge.
The firing mechanism for launching the fluke 12 is comprised of a weighted touchdown rod 40 with a square base pad 42, a safe-and-arm device 14 (S&A) and a power package 16 with a battery supply and electronic circuitry to sequentially energize two solenoid valves 44, and 48 (FIG. 2) within the safe-and-arm device 14. The touchdown rod 40 is attached to the fluke l2 and extends beyond its tip. The rod 40 slides freely when frontal force equalling the resistance supplied by one-fourth psi shear strength soil acts upon it. The force required to cause a bearing capacity type failure in one-fourth psi soil is equivalent to a water drag force on the rod 40 occurring at 17 feet per second, which is considerably greater than the lowering velocity, approximately two feet per second, thus providing a satisfactory margin of safety.
The safc-and-arm device 14, FIG. 2, consists ofa cartridge of high pressure nitrogen 46 1 100 psi), an inflator 47, a 1200 psi volt 2-way, normally closed solenoid valve 44, a 750 psi 24 volt 3-way, normally vented to S&A chamber solenoid valve 48, a 440 psi ilO /o gold shear disc 50, a firing pin piston/cylinder 52, a detonator 54 mounted in a spring return out of line plunger 62, a lead cup 56, and a lead block 58. These are all contained in an aluminum housing 60. To minimize cost and ensure high reliability, that portion of the safeand-arm device 14 mounted in metal block 64 is a readily available and a highly reliable proven system, from the SUS (Signal Underwater Sound) MK 59 series of which several hundred thousand units were manufactured and used with very good safety and detonation records.
As the anchor system is lowered, hydrostatic pressure arms both the electron power package 16 and the safeand-arm device 14. The power package 16 is armed by a pressure switch, while the safe-andarm device 14 is armed by the spring-loaded arming plunger 62 moving into the in-line position. Firing will occur upon touchdown in water depths of 100 feet or more. The power package 16 and safe-and-arm device 14 remain in this armed condition until touchdown or until being recalled above the arming depth, in which cases they both would disarm automatically.
When the touchdown rod 40 contacts the seafloor, a magnet 66, located atop the touchdown rod 40, moves in close proximity to a fluke-mounted magnetic switch 68, momentarily closing it. This energizes power package 16 which in turn activates the three-way valve 48, providing a gas flow path to the shear disc 50. The twoway valve 44, is activated after a 30 millisecond delay in the power package 16 to ensure that the three-way valve has time to change state. The gas from cartridge 46 passes through both valves and the pressure above the shear disc increases until it ruptures at approximately 400 psi. After rupture, the pressure acts on the top of the firing pin 52, pushing it down like a piston until it strikes the detonator 54. This sets off the detonator 54, which in turn sets off the lead cup 56 and the lead block 58. The shock waves set up by the high order detonation travels across the gap between the end of the lead block 58 and fires the primer of a cartridge case in the gun barrel, shown in detail in FIG. 3.
The gun barrel 24 is a smooth bored tube employing a special polyethylene obturator 72 to allow use of some existing military gun tubes having partially tapered bores. Since the piston 26 is muzzle loaded, the obturator disc 72 must be loaded with the cartridge case 74. This is accomplished by fashioning the disc 72 to serve also as the cartridge case 74 closure plug. Pressurization of the cartridge case 74 forces the obturator/plug 72 against the piston 26 base. As the piston 26 is accelerated down the gun tube 70, the plastic obturator 72 flows to provide obturation over the entire firing cycle.
The breech block 20 was designed to mate to the existing breech threads on the gun tube 70. The safe-andarm device 14 is inserted into the breech block 20. The gun barrel assembly 24 is attached to the reaction vessel 22 of the launch vehicle 10, as shown in FIG. 1.
Different flukes are needed to satisfy performance requirements in seafloor sediments and in rock. To satisfy anchoring requirements in seafloor sediments, two flukes are provided. One fluke for sand and stiff clay (sand fluke) and one for soft clay (clay fluke). The basic shape of these sediment flukes is the same and is illustrated in FIG, 4; the only difference being that the clay fluke is a little longer than the sand fluke. To ensure that the fluke mass and drag area were balanced about the piston 26, the basic shape is a bent-plate configuration. The flukes are streamlined for deep penetration, in order to obtain high holding capacities after keying.
One principal feature of the sediment fluke is the technique used for keying. This quick-keying feature is similar to the keying arrangement disclosed in US. Pat. No. 3,621,805 of .I. E. Smith filed Feb. 2, 1970. However, there is no mechanical connection between the end of the piston extension arm 28 and the fluke 12 at their contact point. The fluke 12 is held tight against the piston extension arm 26 by turnbuckles 34 before launching, as shown in FIG. 1. The keying mechanism is comprised of a down haul cable 76 (FIG. 1), piston extension arm 28, link bar 30, coupling link 32, and a keying arm provided by a plate 80 attached to the fluke 12.
The sediment fluke design, shown in FIG. 4, is comprised of a plate 82 bent to provide an included angle of approximately having a streamlined tip 84 and a cut out portion in the rear indicated at 86. The cut out portion 86 is to accommodate the piston extension arm 28. A receptacle 88 is attached to the fluke at the forward end of the cut out portion 86 to provide a surface against which the piston extension arm 28 can push. The receptacle 88 can be a flat circular pad, but preferably is slightly recessed to receive the piston extension arm 28. A steel pipe welded at the forward end of cut out 86 is suitable. Vertical plate 80 is attached on top of the fluke R2 to provide a centrally located keying arm perpendicular to the axis of the fluke 12. The plate 80 may be any shape as long as the keying arm eccentricity required is achieved.
Configuration parameters for both the sand fluke and clay fluke are substantially the same. The length to width ratio of the fluke in both cases is approximately two and, as previously indicated, the included angle is l40 in the bent plate 82. This 140 included angle is for the purpose of ensuring that the fluke centers of mass and frontal drag are situated beneath the piston to guarantee straight, uniform vertical travel into the seafloor. The length of the keying arm provided by plate 80 to provide optimum keying eccentricity should be approximately 0.3 L (L=fluke length) to cause keying in a distance equal to about 1% L measured from the fluke tip. The top, or rear, of the fluke 12, therefore, moves less than the fluke length before keying. Tests indicated that keying actually occurred somewhat quicker than the estimated optimum value. Rapid keying ensures that the anchor, once established, will function as a deep anchor; an anchor whose capacity is not significantly affected by small, upward movement.
Steel plates 90 may be welded to the fluke 12 at the junction of the vertical plate 80 and bent plate 82 to increase the fluke stiffness and provide support for the piston extension arm receptacle 88. This also provides some fairing so that receptacle 88 is not so blunt which reduces drag and improves penetrability. Since the cutout 86 of the bent plate 82 may somewhat weaken it, stiffening bars 92 may also be provided. Penetrability of the fluke 12 may also be improved by chamfering the nose 84 to provide a sharp edge.
The rock fluke design, shown in FIG. 5, is a three fin arrowhead-shaped projectile having approximately a two-to-one taper to the nose 94. Tests indicated that this configuration developed, for a given amount of penetration energy, about the same or better holding capacity than other shapes. Further, since penetration may not be sufficient to bury the fluke, a three-fin fluke is more desirable than other shapes because it affords increased moment resistance to randomly directed loads. Test data also indicated that large fluke serrations are unnecessary; a fluke with a roughened surface is as effective.
The rock projectile includes the fluke and piston. The piston is not fixed to the fluke shaft 100; it fits over the shaft 100 and can separate during penetration. The nose 94 has a length-todiametcr ratio equal to 3 because this is found to be the most effective rock penetrating shape. The nose must remain intact on impact to properly fracture the rock to allow the weaker 3-fin portion to penetrate without damage. For this reason, one inch thick, I00 ksi yield (4140) steel was believed necessary for the fins and center shaft 100 while 160 ksi yield (4340) steel was believed necessary for the fluke nose 94. While different steels for the nose and central shaft may provide some advantages, it was generally found to be unnecessary. The same steel used in the central shaft can be used in the nose (one continuous piece). The nose-tip 104 was blunted at 1 /2 inches from What would have been the tip at an included angle of approximately 100 to eliminate tip bending or hooking during penetration.
The fluke is preferably about three feet long, and the point of cable attachment is in a cable socket 106 in the vertical fin 108 about two feet above the tip of the fluke. The vertical fin 108 is slightly shorter than the other two fins to provide an eccentric connection point. The preferred. length was partially predicted on anticipated penetration depths in basalt of between 2 and 8 feet. The three-foot length was also chosen because of weight considerations and the need to maintain structural integrity and use the three-fin configuration. The three fins can be approximately equally spaced but in order for holes 1 10 to match up with connecting gear on launch vehicle 10, these fins have the same included angle (140) as the sediment fluke 12.
The basic rock fluke shown is a tapered three-fin central shafted projectile having several advantages over prior art flukes. It has a tapered nose for good penetration and multi-directional stiffness for good holding capacity. The three-fin configuration with a central shaft 100 provides the multi-directional stiffness if complete penetration does not occur. Also, the cable attachment socket in the vertical fin provides an eccentric connection point. Thus, the fluke is loaded somewhat eccentrically after embedment. This helps wedge the fluke and increases holding capacity. As with the sediment fluke, the center of mass and drag are centered beneath the piston to ensure streamlined penetration. Prior theory on developing a good rock anchor suggested using a shaped charge prior to projectile penetration. However, tests with this rock fluke indicate that this is unnecessary. The rock fluke is attached to the launch vehicle in the same manner as the sediment fluke. That is, the piston 98 is tightly held in the gun barrel by the turnbuckles 34, brackets 36 and shear pins 38 (see FIG. 1) through holes 110 in two of the fins of the rock fluke.
The operation of the anchor system is demonstrated in FIGS. 6, 7 and 8, which show the embedment and keying of the sediment fluke 12. The embedment of the rock fluke is substantially the same, except there is no keying involved. The anchor system illustrated in FIG. 1 is designed to be control-lowered to the seafloor and to be functional in water depths from 100 feet to 20,000 feet. Above 100 feet, safety switches prevent activation as described above. When the touchdown probe 40, protruding below the fluke tip, contacts the seafloor, the firing sequence is initiated. The fluke 12 and piston 26 are restrained from movement by the shear pins 38 until pressure within the gun barrel reaches a predetermined amount (approximately 3,000 psi). At this point, the fluke l2 and piston 26 which are connected to a main lowering line through a flaked down haul cable 76 attached to the piston extension arm 28, is propelled into the seafloor at velocities up to 400 feet per second.
FIG. 6 shows the fluke 12 penetrating the seafloor. The piston extension arm 28 is maintained in contact with the fluke by inertial forces until penetration is complete. After penetration is complete, a small pull on the main cable 112 initiates keying of the fluke (i.e.,
begins rotation of the fluke 12 into its resistive position). When keying is initiated, the piston extension arm is automatically separated from the fluke and the link bar rotates until the piston extension arm 28, link bar and coupling link 32 are aligned. A force is then applied to the keying arm eccentricity of the vertical plate 80 attached to the fluke 12, causing it to rotate until the keying arm is aligned with the piston arm extension link bar 30 and coupling link 32, as shown in FIG. 8. The rapid keying arrangement shown, minimizes keying distance and upward movement of the fluke during keying. This ensures that the anchor, once established, will function as a deep anchor whose holding capacity is not significantly affected by the small upward movement.
The propellant system is designed to give the anchor projectile (fluke and piston) a velocity of 300 to 440 feet per second. To achieve these velocities with a relatively short gun barrel, very high acceleration is required. Propellant charge weights needed to achieve these .nuzzle velocities and to optimize performance are determined from the known characteristics of the propellant, the gun tube, the operable water depths, and the anchor projectile weights.
A number of alternatives will become obvious to those of ordinary skill in the art in light of the above teachings. For example, the keying mechanism of the sediment fluke 12 can be varied by attaching the down haul cable 76 directly to the keying arm eccentricity and passing it through the piston extension arm. Thus, a small pull on the down haul cable will separate the piston arm extension and, at the same time, cause keying of the sediment fluke. In this case, the link bar 30 and coupling link 32 connected to the piston extension arm 28 will be eliminated. An even simpler arrangement would be to connect the down haul cable 76 directly to the keying arm and permit the piston 26 and piston extension arm 28 merely to remain in contact with the fluke by inertial forces. This will function best on a small fluke where less rigidity is required. Thus, when the cable is pulled, the piston and piston extension will be separated from the fluke. This modification, however, may require that the receptacle 88 into which the piston extension arm 28 is received be slightly more complicated in order to ensure that the piston extension arm 28 remains in contact with the fluke until keying is initiated. For example, a tapered end on the piston extension arm 28 and a tapered receptacle 88 could be used to provide more rigidity.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
1. A propellant actuated direct embedment anchor system comprising:
a. a launch vehicle having a propulsion system comprised of a gun barrel and firing mechanism attached to a reaction vessel;
b. a piston means engaging the gun barrel;
c. a fluke assembly attached to said launch vehicle by shear pins and a surface of said fluke assembly held tightly in contact with said piston means prior to firing; said piston means providing an inertial force to said fluke assembly after firing and during penetration of the seafloor by pushing against the fluke assembly surface which is held in contact with said piston means without mechanical connection at the point of contact between said surface and piston means, contact between said piston means and said fluke assembly being maintained during initial and final stages of seafloor penetration by the drag on said fluke assembly being greater than on said piston means;
d. said fluke assembly having a configuration which ensures the centers of mass are situated beneath the piston means during firing and penetration to guarantee straight, uniform travel into the seafloor by the inertial force applied thereto from said piston means;
e. means attached to said piston means operable to cause said piston means to separate from said point of contact between said fluke assembly surface and said piston means and to initiate rotation of the fluke assembly from a vertical position to a position of maximum uplift resistance after penetration and embedment is complete.
2. The anchor system of claim 1 wherein the propulsion system firing mechanism includes a. a safe-and-arm device;
b. a power package for activating the safe-and-arm device;
0. a fluke mounted magnetic switch for energizing the power package;
(1. a freely sliding touchdown rod attached to the fluke fin and extending beyond the fluke tip; said touchdown probe having a magnet which moves in close proximity to the magnetic switch to energize it when the touchdown rod contacts the seafloor.
3. The anchor system of claim 1 wherein the reaction vessel is comprised of a steel tube welded to a plate and having sufficient mass to provide a ratio of launch vehicle mass to piston means and fluke mass of up to three.
4. The anchor system of claim 1 wherein the fluke assembly is of the type for direct embedment in sediment seafloors and includes,
a. a plate bent to form an included angle of approximately said plate having a cutout portion at the rear to accommodate the piston means which pushes against said fluke assembly to impart the inertial force to said fluke assembly;
b. a receptacle attached to the bent plate at the foremost end of the cutout portion against which the inertial force from said piston means can be applied.
5. The anchor system of claim 4 wherein the bent plate provides a fluke length to width ratio of approximately 2.
6. The anchor system of claim 4 wherein the means for rotating the fluke to the maximum uplift resistance position comprises:
a. means for providing a keying arm having a predetermined keying eccentricity; and
b. a keying mechanism attached to said keying arm means.
7. The anchor system of claim 6 wherein said keying arm means is a vertical plate attached to said bent plate to provide a keying arm eccentricity of approximately 0.3 of the fluke length.
8. The anchor system of claim 7 wherein said keying mechanism is comprised of:
a. a rotatable coupling link attached to the vertical plate;
b. a rotatable link bar attached to the coupling link;
c. a piston means extension arm attached to the rotatable link bar with one end fitted into and attached to the piston; means and the opposite end of the piston means extension arm adapted to mate with the receptacle on the fluke and remain in contact with the receptacle during penetration of the seafloor; and
d. a downhaul cable attached to the piston means extension arm so that a small pull on the cable causes the piston means extension arm to separate from the receptacle to initiate keying whereby the fluke is rotated to its position of maximum uplift resistance.
9. The anchor system of claim 1 wherein the fluke assembly is an arrowhead-shaped projectile for direct embedment in rock seafloors and comprises:
a. a central shaft having a nose of predetermined taper;
b. three fins approximately equally spaced on said central shaft, one of said fins being slightly shorter than the other two; and
c. A cable socket provided in the shortest fin to provide eccentricity after embedment.
10. The anchor system of claim 9 wherein the nose on the central shaft has a 3 to l taper and the nose tip is blunted to prevent bending during embedment.
11. The anchor system of claim 10 wherein the exterior surface of the fluke assembly is roughened to increase holding power.
12. A fluke assembly of the type for direct embedment in sediment seafloors comprising:
a. a piston for applying an inertial force to the fluke assembly during penetration of the seafloor;
b. a fluke formed from a plate bent to provide an included angle such that the centers of mass are situated directly below the piston to ensure straight uniform travel into the seafloor; said plate having a cutout portion at the rear to accomodate the piston;
c. a receptacle attached to the fluke at the foremost end of the cutout portion against which the inertial force of the piston can be applied;
(:1. a keying assembly for rotating the fluke from the penetrating position to a position of maximum uplift resistance;
e. said keying assembly comprising means for providing a keying arm having a predetermined eccentricity, and a keying mechanism attached to said keying arm means;
f. said keying arm means being a vertical plate attached to the fluke to provide a keying arm eccentricity of approximately 0.3 of the fluke length.
13. The fluke assembly of claim 12 wherein the fluke is formed to provide an included angle of approximately 14. The fluke assembly of claim 13 wherein the fluke has a length to width ratio of approximately 2.
15. The fluke assembly of claim 12 wherein said keying mechanism is comprised of:
a. a rotatable coupling link attached to the vertical plate; b. a rotatable link bar attached to the coupling link; c. a piston extension arm attached to the rotatable link bar with onev end fitted into and attached to the piston; the opposite end of the piston extension arm adapted to mate with the. receptacle on the fluke and remain in contact with the receptacle during penetration of the seafloor; and d. a downhaul cable attached to the piston extension arm so that a small pull on the cable causes the piston extension arm to separate from the receptacle to initiate keying whereby the fluke is rotated to its position of maximum uplift resistance.